Process and apparatus for producing core yarns



July 4, 1961 E. M. ADKINS, JR 2,990,673

PROCESS AND APPARATUS FOR PRODUCING CORE YARNS Filed Jan. 6, 1954 IN VEN TOR. fuss/Ye M ADKIN JP.

United States Patent 2,990,673 PROCESS AND APPARATUS FOR PRODUCING COREYARNS I Eugene M. Adkins, Jr., Burlington, NC, assignor to CelaneseCorporation of America, New York, N.Y., a corporation of Delaware FiledJan. 6, 1954, Ser. No. 402,453 Claims. (Cl. 57-'-36) This inventionrelates to composite yarns and relates more particularly to theproduction of the type of composite yarns known as core yarns.

Core yarns are textile structures which generally consist of a corematerial, usually a strong fine yarn formed of a plurality of continuousfilaments or staple fibers, more or less hidden within an outer layer ofstaple fibers drafted and twisted around said core material. These coreyarns have been produced by a process termed Belgian doubling in theart, which is carried out on a spinning frame, which frame comprises aplurality of pairs of drafting rolls, including a pair of front rolls,and a spinning bobbin mounted in a twisting and winding device such as aring twister. A roving of staple fibers is led through the draftingrolls to the nip of the front rolls while the thread which is toconstitute the core material is led directly to the nip of said frontrolls, by-passing the other drafting rolls. The core material and thedrafted roving are twisted together as they proceed from the nip of thefront rolls to the spinning bobbin.

Core yarns produced by the Belgian doubling process described above havebeen generally unsatisfactory in that the outer staple fibers do notcompletely cover the core material, particularly when the core yarn isof medium or fine count. This defect is especially noticeable when thecore material and the covering fibers are of different colors or shades.For example, this defect may be readily observed after the dyeing of thecore yarn, since the receptivity of the core material for the dye isusually different from the dye receptivity of the fibers constitutingthe outer layers of the core yarn and union dyeing of the core materialand the covering fibers is, in many cases, difficult or impractical.Thus, cross dyed effects ordinarily are encountered, whetherintentionally or not, so that the incompletely covered dyed corematerial can be seen through the dyed outer fibers and the yarn has anundesirable fiecked or streaked appearance. This appearance hasrestricted the use of core yarns mainly to novelty applications and hasprecluded the use of such yarns to a large extent in woven and knittedfabrics, even though the core material has imparted higher tensilestrength and other desirable physical properties to the yarns.

It is an important object of this invention to provide a method andapparatus for the production of core yarns free from the foregoing andother disadvantages.

A further object of this invention is the provision of a novel anduseful method and apparatus for producing core yarns.

Other objects of this invention will be apparent from the followingdetailed description and claims.

According to one embodiment of this invention a core yarn is produced byfeeding a pair of spaced rovings of staple fibers through the draftingrolls of a spinning frame to the balloon guide of the ring twistingdevice of said frame, while the yarn which is to constitute the centeror core of the core yarn is fed at a predetermined speed between saidspaced rovings to said balloon guide, and is combined with the draftedrovings. The resulting composite filamentary material is twisted, as itpasses to the spinning bobbin, to produce the core yarn. Core yarnsproduced according to this invention comprise a central coresubstantially completely covered by staple fibers.

When dyed such core yarns present a pleasing, uniform unstreakedappearance.

The accompanying drawing is a simplified view, mamly in perspective, ofthe apparatus of this invention.

Referring now to the drawing, reference numerals 11, 12 and 13, 14 and16, 17 designate successive pairs of drafting rolls of a spinning frame,while reference numetal 18 designates generally the ring twistingportion of said spinning frame. In one suitable embodiment the lowerrolls 11, 13 and 16 are fluted, metallic, positively driven rolls, whilethe upper rolls 12, 14 and 17 are covered rolls, pressed against thelower rolls in any suitable manner, as by weights (not shown) and drivenby frictional contact with said lower rolls, all in a manner well knownto the art. The spinning frame is of the type commonly employed for thespinning of ordinary yarn, with the following exceptions: Mounted on thespinning frame, above and slightly behind the front drafting rolls 16,17 is an independently driven feed roll 19 (which may be driven by anysuitable means, as through gear 20) for supplying the yarn 21, which isto constitute the center, or core, of the core yarn, to said frontdrafting rolls. Riding on the feed roll 19, and pressed thereagainst inany suitable manner, as by means of a weight (not shown), is a top roll22, covered with any suitable material such as cork or synthetic rubber,while above the nip of the rolls 19 and 22 there is mounted a guide 23for receiving the yarn 21 from any suitable source. The covering, or cot24, of the upper front roll 17 is provided with a narrow circumferentialgroove 26 of width and depth sufficient to accommodate the yarn 21 sothat said yarn 21 may pass through said groove at a speed independent ofthe speed of said front roll 17. Behind the rear drafting rolls 11, 12there are mounted a pair of spaced funnel-shaped guides or trumpets 27and 28 for receiving a pair of spaced rovings 29 and 31 of staple fiber;these two trumpets 27, 28 replace the single trumpet usually employed onspinning frames. It is to be understood, of course, that a conventionalspinning frame comprises a large number of identical spinning positionsfor spinning a correspondingly large number of yarns, and that thechanges indicated above may be made at one, several, or all of saidspinning positions, as desired. Advantageously, the roll 19 extends theentire length of the spinning frame while separate rolls 22 are providedfor each spinning position. Thus, each roll 22 may be raised to stop thefeed of the yarn 21 which is in contact therewith, without interferingwith the feed of similar yarns at other spinning positions, so that itis easy to start up operation or to replace a broken yarn at any onespinning position without affecting the other spinning positions.

To start the operation of spinning the core yarn, the yarn 21 isthreaded through the guide 23, the nip of the rotating rollers 19 and22, the groove 26 in the upper front roll 17 and the balloon guide 32and traveler 33 of the ring twister 18 and is wrapped onto an emptydriven bobbin 34 mounted in said ling twister. Advantageously, thebobbin 34 is held stationary, as by a brake, when the yarn 21 is firstwrapped thereon and then is allowed to rotate so as to wind the yarn onthe bobbin. The rovings 29 and 31 are drawn from suitable separatesources through the guides 27 and 28, between the successive pairs ofrotating drafting rolls 11, 12 and 13, 14 to the nip of the rotatingfront rolls 16, 17, said rovings being maintained in spaced condition.The drafted rovings emerging from the nip of the front rolls 16, 17 arethen thrown, manually or by any suitable mechanical device, onto theyarn 21 travelling to the balloon guide '32, causing said draftedrovings to begin to twist around said yarn 21. Thereafter, the rate offeed of the yarn 21 is adjusted relative to the rate of feed of thedrafted rovings in order to ensure that in'the resulting 'core yarn thecentral core is completely covered. This adjustment of the feed ratesmay be accomplished by maintaining the speeds of the drafting rolls 11,12, 13, 14, 16, 17 constant while regulating the speed of the feed roll19, which feed roll may be driven in any suitable manner, e.g. through atrain of gears connected to the driven front roll 16.

The rate at which it is necessary to drive the feed roll 19 in order toobtain a core yarn in which the yarn 21 is substantially completelycovered by the staple fibers of the rovings 29 and 31 will depend onsuch factors as the type, fineness and weight per unit length of therovings 29 and 31 and similar parameters of the yarn 21. However, thecorrect rate can be determined in any instance in a simple manner byexamining the core yarn being produced and varying the speed of the feedroll 19 accordingly. Examination of the core yarn to determinecompleteness of covering is particularly easy when the core material andthe covering fibers are of different colors, e.g. when the rovings aremade of pigmented fibers. When inspection of the core yarn shows thatthe central thread is not completely covered the speed of the feed roll19 should be decreased, while when the amount of coverage is greaterthan that desired the speed of the feed roll 19 may be increased. Afterthe ratio of the speed of feed roll 19 to the speed of front rolls 16and 17 has been determined by preliminary trials for any given rovingsand yarns and any given spinning conditions, this ratio is maintainedconstant during the spinning operation.

Because of the presence of the groove 26, the front roll 17 acts as aguide for directing the yarn 21 substantially into the plane of thedrafted rovings without substantially affecting the speed of said yarn21. Naturally, the groove must be larger when a thick yarn 21, such as arubber yarn, is employed, than when a fine yarn such as fine nylon yarn,is used.

The process and apparatus of this invention may be used with a widevariety of textile fibers, and are particularly suitable for use withsynthetic textile fibers, such as fibers of cellulose acetate or othercellulose esters and ethers; fibers of polyamides such as nylon; fibersof vinyl polymers such as polyvinyl alcohol or the polymers andcopolymers of acrylonitrile, vinyl chloride and ethylene; fibers ofpolyesters such as polyethylene terephthalate; cellulose fibers such asviscose rayon or high tenacity fibers of saponified stretched celluloseacetate; or fibers made from rubber latex. It is desirable, for bestresults, to employ a yarn of continuous filaments as the centralportion, or core, of the core yarn. Thus, excellent results have beenobtained when the yarn making up the central core is composed ofcontinuous filaments of cellulose acetate, saponified stretchedcellulose acetate or nylon while the rovings are made up of staplefibers of cellulose acetate, each staple fiber having a denier of about2 or 3 and an average length of about 2 inches, said rovings having atotal denier of the order of about 900 to 5300 each, for example, andhaving a small amount of twist, e.g. a twist of 0.8 to 2.0 turns perinch. It has been found advantageous to employ a yarn of continuousfilaments which has no initial twist or which has an initial twist in adirection which is the same as the direction in which the composite orcore yarn is to be twisted. However, if desired, the initial twist ofthe yarn which is to constitute the central core may be in a directionopposite to the direction in which this yarn and the drafted rovings areto be twisted together.

As is well known, it is not possible, on a practical basis, to producevery fine yarns, i.e. yarns of high count, composed of those staplefibers which have relatively low tenacities, e.g. cellulose acetate.However, by the use of this invention there have been produced, on apractical scale, very fine core yarns comprising continuous filaments ofcellulose acetate surrounded by staple fibers of the same material.These core yarns are much finer than those produced solely from staplefibers of cellulose acetate and have properties superior to those ofsuch staple fiber yarns, but have the general appearance of the staplefiber yarns. Other specific examples of core yarns which may be producedaccording to this invention include core yarns composed of one or morecontinuous filaments of rubber surrounded by staple fibers of anydesired material, e.g. cellulose acetate or viscose rayon; core yarnscomposed of spun or continuous filament yarns of polyethyleneterephthalate surrounded by blends of cellulose acetate staple fibersand wool fibers; core yarns composed of continuous filaments ofcellulose acetate surrounded by blends of nylon and cellulose acetatestaple fibers; core yarns composed of continuous filaments ofpolyethylene terephthalate or nylon covered by staple fibers ofpolyvinyl alcohol; and core yarns composed of continuous filaments ofstretched cellulose acetate, either saponified or not, covered by ablend of staple fibers of cotton and stretched saponified celluloseacetate.

Although this invention is particularly applicable to the spinning ofyarn, it may also be employed for the production of cored rovings byintroducing two spaced ends of sliver, having adenier of, for example,about 12,000 to 45,000 instead of one, into a conventional roving frame,while introducing a yarn, between said ends of sliver, through acircumferential groove cut into the top front roll of said roving frame.

It is to be understood, of course, that while the invention has beendescribed using a ring and traveler for effecting the twisting of theyarn and the drafted fibers, this twisting operation may be carried outin any other suitable manner, e.g. by the use of a cap or a flyer, bothof which are well known to the art. In addition, the drafting rolls ofthe spinning frame may be provided, if desired, with one or more of theaprons conventionally employed with such rolls.

The following example is given to illustrate this invention further.

Example A pair of rovings, each of 1300 denier, and each composed ofpigmented black crimped staple fibers of cellulose acetate, said fibershaving an average denier of about 2 and an average length of about 2inches, are fed to the rear rolls of a ring-spining frame modified inaccord ance with this invention, which spinning frame is provided withan apron, of conventional construction, for transporting the rovings tothe front rolls from the drafting rolls just behind said front rolls.The rear rolls of the spinning frame are driven at 1.3 feet per minute,while the front rolls of said frame are driven at 33.8 feet per minute.A yarn of white continuous filaments of stretched saponified celluloseacetate of high tenacity, said yarn having a denier of 30, is fed to thegroove in said front rolls at a speed of 32 feet per minute and isthrown onto the spinning bobbin of said frame, which bobbin is rotatedat 9,000 revolutions per minute. The drafted rovings leaving the frontrolls of the spinning frame are thrown onto the yarn of continuousfilaments passing to the spinning bobbin. The resulting core yarn has auniform black appearance, the white central thread being completely anduniformly covered by the black pigmented staple fibers.

It is to be understood that the foregoing detailed description is givenmerely by way of illustration and that many variations may be madetherein without departing from the spirit of my invention,

Having described my invention, what I desire to secure by Letters Patentis:

l. A frame for the production of core yarns, said frame comprising apair of guides for receiving a pair of spaced rovings of staple fiber, aplurality of rolls for receiving said rovings from said pair of guidesand for drafting said rovings in spaced condition and for positivelyfeeding said drafted rovings to a point, means for positively feeding ayarn to said point, and means for twisting the resulting composite ofrovings and yarn to wrap said staple fibers around said yarn, theconstruction and arrangement being such that said rovings are maintainedseparate and then converge at said point.

2. Apparatus for the production of core yarns, said apparatus comprisinga driven yarn package support for winding and twisting filamentarymaterial fed thereto, a pair of spaced guides, each receiving a rovingof staple fiber, a plurality of rolls for receiving said rovings fromsaid pair of guides and for drafting said rovings in spaced condition,said rolls including a pair of cooperating front rolls for positivelyfeeding said drafted rovings to said driven yarn package support, andmeans for positively feeding a yarn to said driven yarn package supportat a linear speed lower than the linear speed of said front rolls, theconstruction and arrangement being such that said rovings are maintainedseparate and then converge from said front rolls to said yarn.

3. Apparatus as set forth in claim 2, wherein said front rolls havespaced operative portions for engaging said rovings, and means forguiding said yarn between said spaced operative portions.

4. Apparatus as set forth in claim 3, wherein said means for guidingsaid yarn comprises a circumferential groove, between said spacedportions, for receiving and guiding the yarn from said means forpositively feeding said yarn.

5. Apparatus as set forth in claim 4, wherein said means for positivelyfeeding said yarn comprises a pair of feed rolls mounted above saidfront rolls, and said front rolls include upper and lower rolls, saidupper roll being grooved circumferentially between said spaced portionsfor receiving said yarn from said feeding rolls.

6. Process for the production of core yarns, which comprises rotating ayarn package support for winding and twisting filamentary materialthereon, positively feeding a plurality of spaced rovings of staplefibers to said rotating package support at a predetermined linear speed,positively feeding a yarn at a lower predetermined linear speed to saidyarn package support and between said rovings, said rovings convergingto meet at said yarn, whereby the rotation of said yarn package supporttwists the resulting composite filamentary material to wrap said staplefibers around said yarn.

7. Process as set forth in claim 6 in which said yarn is a continuousfilament yarn.

8. Process for the production of core yiarns which comprises rotating ayarn pacage support for winding and twisting filamentary materialthereon, drafting a pair of spaced rovings of staple fibers, positivelyfeeding the resulting drafted rovings to said yarn package support at apredetermined linear speed, positively feeding a yarn at a lowerpredetermined linear speed to said yarn packagesupport and between saidrovings, said rovings converging to meet at said yarn, whereby therotation of said yarn package support twists the resulting compositefilamentary material to wrap said staple fibers around said yarn.

9. Process as set forth in claim 8 in which said drafted rovings arepositively fed to said rotating yarn package support by engagement ofsaid drafted rovings between spaced operative portions of a pair ofdriven front rolls, and said positively fed yarn passes around one ofsaid front rolls in a groove in said roll without being engaged by theother of said front rolls.

10. Process as set forth in claim 8 and in which said yarn is asubstantially inelastic continuous filament yarn.

11. Process as set forth in claim 8 and in which said yarn is asubstantially inelastic stretched saponified cellulose acetatecontinuous filament yarn of high tenacity.

12. Apparatus for producing core yarns comprising: a ring spinning framehaving a roving creel, drawing rolls, spindles and rings and travelers;a support for a supply of continuous filament yarns, a yarn feed rollfor positively advancing a continuous filament yarn from such supplytoward each pair of front drawing rolls; means for driving said yarnfeed roll at a surface speed slightly less than the surface speed ofsaid front drawing rolls; and yarn guide means for guiding thecontinuous filament yarns from said yarn feed rolls between said frontdrawing rolls in longitudinal alignment with the centerline of ribbonsof staple fibers passing between said front drawing rolls.

13. Apparatus for producing a core yarn comprising: a ring spinningframe having a roving creel, drawing rolls, a spindle and a ring andtraveler; a support for a supply of continuous filament yarn; a yarnfeed roll for positively advancing a continuous filament yarn from suchsupply toward the front drawing rolls; means for driving said yarn feedroll at a surface speed slightly less than the surface speed of saidfront drawing rolls; and yarn guide means for guiding the continuousfilament yarn from said yarn feed roll between said front drawing rollsin longitudinal alignment with the centerline of a ribbon of staplefibers passing between said front drawing rolls.

14. Apparatus for producing a core yarn comprising: a ring spinningframe having a roving creel, drawing rolls, a spindle and a ring andtraveler; a support for a supply of continuous filament yarn; yarn feedmeans for positively advancing a continuous filament yarn from suchsupply toward the front drawing rolls; means for driving said yarn feedmeans at a rate to advance said continuous filament yarn at a speedslightly less than the surface speed of said front drawing rolls; andyarn guide means for guiding the continuous filament yarn from said yarnfeed means between said front drawing rolls in longitudinal alignmentwith the centerline of the ribbon of staple fibers passing between saidfront drawing rolls.

15. Apparatus for producing core yarns comprising: a ring spinning framehaving a roving creel, drawing rolls, spindles and rings and travelers;a support for a supply of continuous filament yarns, a yarn feed rollfor positively advancing a continuous filament yarn from such supplytoward each pair of front drawing rolls; means for driving said yarnfeed roll at a surface speed slightly less than the surface speed ofsaid front drawing rolls; and yarn guide means for guiding thecontinuous filament yarns from said yarn feed rolls between said frontdrawing rolls in longitudinal alignment with the centerline of staplefibers in ribbon form passing between said front drawing rolls.

References Cited in the file of this patent UNITED STATES PATENTS128,618 Harris July 2, 1872 2,061,498 Bird Nov. 17, 1936 2,076,270Harris Apr. 6, 1937 2,210,884 Chittenden et a1. Aug. 13, 1940 2,234,338Franke Mar. 11, 1941 2,263,614 Cote Nov. 25, 1941 2,309,095 Bry Ian. 26,1943 2,526,523 Weiss Oct. 17, 1950 FOREIGN PATENTS 13,939 Great Britainof 1896

